ES2269963T3 - ENDOTHERMAL ENGINE WITH ROTATING PISTONS. - Google Patents

Abstract

The endothermic 4-stroke rotating pistons engine comprises: a stator having an internal stator chamber provided with a fluid exhaust pipe and a fluid suction duct, a drive shaft traversing said chamber coaxially, and a rotor connected to the drive shaft and during its rotation having surfaces facing on parts of the surface of the stator chamber. <??>The engine is characterized in that the rotor comprises rods functioning as cranks, each with one end connected rigidly to the drive shaft and with the other end hinged to a respective prismatically shaped piston, said piston having one convex face surface ending on two opposite sides with two apical rectilinear edges parallel to the axis of the axis of the drive shaft, with said face always facing parts of the surface of the stator chamber during rotation of the drive shaft and displaying a curvature never greater than the curvature of said parts, and in that the stator chamber displays a cross section with ovoidal profile symmetrical with two axes perpendicular to each other and shaped to ensure for each position of the rotor a sealed contact with said apical edges. <IMAGE>

Description

Endothermic motor with rotary pistons.

The present invention relates to an engine Endothermic with rotary pistons.

Background

Internal combustion engines with pistons they are mostly of the alternative type, that is, they present pistons with alternative movement.

As alternative piston engines they suffer from some inconveniences such as, for example, their weight,  size, construction complexity, unbalanced layout of the moving masses and the specific power relatively limited, in the past it has been experimented with combustion engines internal with rotary pistons of which the one that reached the practical realization and is still in use is the engine called Wankel by the name of one of its inventors.

The operating principle of this engine Wankel (subject to various patents among which is the US Patent No. 2,988,065) is briefly set forth below with reference to the attached diagrammatic figures 1A-1D (cross-sectional views) and 1E (view in exploded order).

It includes a "a" stator that has a camera internal "b" cylindrical shape with a cross section of trocoidal profile, whose surface is concave except in two zones opposite medians "c", in which it is slightly convex. A rotor "f" located inside the chamber is connected to a tree drive "d" (which coaxially crosses the camera) by a cam "e" with circular profile eccentrically attached to the drive shaft, said rotor consisting of a body prismatic whose cross section has the profile of a triangle with curvilinear sides. During operation of the coupled rotor in a rotating way to the circular cam, the rotation around the axis of the cam causes the rotation of said axis around the axis of the drive shaft and, consequently, the rotation itself tree. This takes place with the contribution of two sprockets "g" and "h" one inside another, of which the first "g" is fixed to the drive shaft and is coaxial with this and the second "h" meshes with the first and is subject to rotor.

In each of the three hollow spaces delimited by the surface of the stator chamber and by the peripheral surface of the rotor runs of the cyclic motor operation similar to those of engines alternative endothermic four cycles.

Figures 1A-1D illustrate the way in which the races follow each other in each of the three hollow spaces with every 90º turn of the tree drive and with a corresponding 30º rotation of the rotor. In effect, to the rotor positions illustrated in the figures correspond the following races in the hollow spaces (f1), (f2) and (f3) adjacent to the sides f1, f2 and f3 of the rotor.

Position of Figure 1A

(f1):

end of the escape run through of the exhaust duct "l" and beginning of the aspiration through the aspiration line "m"; (f2): beginning of the compression stroke; (f3) expansion run that Follow the ignition of the mixture by the spark plug "i".

Position of Figure 1B

(f1):

continuation of the career of aspiration; (f2) compression stroke; (f3) career maximum of expansion and beginning of escape.

Position of Figure 1C

(f1):

continuation of the career of aspiration (f2); ignition and maximum compression stroke; (f3) continuation of the escape race.

Position of Figure 1D

(f1):

end of the suction stroke; (f2) expansion stroke that follows the ignition of the mixture; (f3)  continuation of the escape race.

They are appreciated by the previous description that in the Wankel engine there are three useful cycles (one for each space hollow) with each revolution of the rotor, to which three correspond revolutions of the drive shaft, and therefore there is a cycle useful with every revolution of the tree.

The document DE-B-1295569 describes an engine endothermic with rotary pistons with an inner chamber, a drive shaft and stems with one end connected rigidly to the drive shaft and the other articulated end with a respective piston prismatically, having the pistons a convex surface with two rectilinear apical edges. He Sectional profile of the inner chamber is ovoidal and constructed adopting for two opposite parts an arc of circumference and for the remaining parts some curves obtained point by point by the trajectory drawn by an apical edge of one piston when the other edge moves along one of the arches of circumference.

Objectives of the invention

The objective of the present invention is the realization of an endothermic motor with rotary pistons that, in comparison with prior art engines and, in particular, with the Wankel engine, I would present at least one of the following advantages:

-

 higher simplicity of construction;

-

 a highest number of useful cycles for each revolution of the tree drive,

-

 higher specific power, and

-

 a more balanced arrangement of mobile masses.

Summary of the invention

According to the inventive solution of the scope more wide, the endothermic motor with rotary pistons contemplates a operating cycle comprising suction strokes, compression, expansion and fluid leakage and the presence of:

-

 a stator that has an internal cylindrical stator chamber closed at its ends by two base plates and provided with a chamber fluid exhaust duct and a duct fluid aspiration into the chamber,

-

 a drive shaft that crosses said chamber coaxially, Y

-

 a rotor connected to the drive shaft and which, during its rotation it has surfaces facing parts of the surface of the stator chamber and delimits with said parts cameras of variable volume work with the rotation of the tree drive,

at that:

-

 he rotor comprises rods that function as cranks, each with one end rigidly connected to the drive shaft and with the other end articulated to a respective piston so prismatic

-

 saying piston has a convex front surface that ends in two opposite sides with two apical rectilinear edges parallel to the axis of the drive shaft, said face always facing during the rotation of the drive shaft to parts of the surface of the stator chamber and presenting a never greater curvature that the curvature of said parts, and

-

 the stator chamber features a cross section with profile ovoidal symmetric with respect to two axes perpendicular to each other and configured to ensure a contact in each rotor position sealed with said apical edges, and

-

 be denominate "l" and "L" to the lengths of the semi-axes more short and longer, respectively, of the ovoidal profile of the camera of the stator and is called "r" to the value 0.5 \ sqrt {L2} + l 2, the apical edges of each piston representing a distance of 2 \ cdotr to each other.

The engine is characterized by:

-

 he joint axis of each piston is located in the plane defined by the two apical edges and is equidistant from the themselves,

-

 the distance from the axis of the joint to the axis of the shaft drive is "r",

-

 he Stator chamber profile is expressed in polar coordinates by the equation: \ rho (\ theta) = 2r \ cdot cos (\ Psi_ {M} - \ Psi_ {m}) \ cdot sen ^ {2} \ theta + \ Psi_ {m})

in which \ Psi_ {M} = arccos (l / 2r) and \ Psi_ {m} = arccos (L / 2r).

Preferred embodiments are indicated in the following claims.

Drawings

To better clarify the objectives and characteristics of the present invention are described as below and are illustrated in the accompanying drawings (figures 2 to 13) exemplary preferred embodiments thereof, in the that:

Figure 2: shows a perspective view schematic of an engine mounted in accordance with this invention,

Figure 3: shows an exploded view of the motor of figure 2,

Figures 4A-4D: show some schematic cross-sectional views of the same engine with different angles of rotation of the drive shaft,

Figure 5: shows a schematic view of the stator chamber and rotor illustrating a criterion of preferred sizing of the rotor and chamber,

Figures 6A-6D: show some axonometric views of body 1c of figure 3,

Figures 7A-7B: show some axonometric views of the plate 1a of figure 3,

Figures 8A-8E: show some axonometric views of a tamper of figure 3,

Figures 9A-9B: show some axonometric views of cranks 3a and 3a 'of figure 3;

Figures 10A-10B: show axonometric views of a piston pin that acts as a joint, and

Figures 11, 12 and 13A-13B show the equivalent to figures 3, 4, 9A and 9B in case The engine is made with three rotating pistons.

Preferred embodiments of the invention

Figures 2, 3 and 4A-4D illustrate the idea of the solution on which the present is based invention.

In effect, the endothermic engine according to The present invention requires an operating cycle that It includes some suction, compression, expansion and fluid leakage and the presence of:

-

 a stator 1 comprising a cylindrical body 1c with a chamber of internal cylindrical stator closed at its ends by two plates of bases 1a-1b and provided with a conduit 1d for the fluid leakage from the chamber and a conduit 1e for aspiration of fluid into the chamber,

-

 a drive shaft 2 that crosses said chamber coaxially, Y

-

 a rotor 3 connected to the drive shaft and which, during its rotation, it has surfaces facing parts of the surface of the stator chamber and delimiting with said parts said chambers  of work whose volume varies with the rotation of the tree drive

The engine features the following features:

-

 he rotor 3 comprises two stems 3a, 3a 'that function as cranks and each of them with one end rigidly connected to the tree drive and the other end articulated with a respective piston 3b, 3b 'prismatically,

-

 he Piston mentioned above 3b, 3b 'presents a face 3b_, 3b'_ with a convex surface and ending on two opposite sides with two apical rectilinear edges 3b ^, 3b '^ parallel to the axis of the tree  drive,

-

during the rotation of the drive shaft, the surface mentioned previously it is always facing parts of the surface of the stator chamber and has a curvature never greater than the curvature of these parts (see figures 4A-4D),

-

 the stator chamber features a cross section with profile ovoidal symmetric with respect to two perpendicular axes (x, y) each other and configured so that it is secured for each position of the rotor a sealed contact with both apical edges mentioned 3b ^ (3b '^).

Figure 5 shows a schematic view of the stator chamber and rotor illustrating a criterion of preferred sizing for them.

According to this criterion, having called "L" and "l" to the lengths of the two semi-axes of the ovoidal cross section profile of the stator chamber and having called "r" to the value 0.5 \ cdot \ sqrt {L2} + l 2, each piston 3b, 3b 'is sized such that the distance between its apical edges is equal to 2r, while the joint axis connecting the crank 3a, 3a 'to the respective piston 3b, 3b 'is located in the plane defined by said edges apical and equidistant from them, and the crank 3a, 3a 'is sized in such a way that the distance between the axis of the joint mentioned above and the shaft of the tree drive equals "r". Adopting these criteria of preferred sizing, the curve that represents the profile of the stator chamber is expressed in polar coordinates by the following equation:

\ rho (\ theta) = 2r \ cdot cos ((\ Psi_ {M} - \ Psi_ {m}) \ sen ^ {2} \ theta + \ Psi_ {m})

in the that:

\ Psi_ {M} = arccos (l / 2r)

\ Psi_ {m} = arccos (L / 2r)

Indeed, with these criteria of sizing, the angle in the center subtended by the rope PP '(figure 5) is always straight and the coordinates \ rho and \ rho' of any two points of the curve angularly spaced in 90º always satisfy the relation \ rho2 (\ theta) + \ rho '2 (? + \ pi / 2) = (2r) 2, and this ensures that, for each rotor position, the margins apicals are always in contact with the surface of the stator

According to a preferred choice, the L / l ratio is assumed within a range between 1.15 and 1.35.

Assuming, in particular, L / l = 1.28 and sizing l = 7.8 cm, L = 10 cm, r = 6.34115 cm and \ rho (\ theta) = 12.6823 \ cdot cos (0.246 \ cdot sin 2 \ + 0.6624) cm.

In each of the two hollow spaces delimited by the surface of the stator chamber and by the peripheral surface of the rotor pistons, some occur cyclic engine operating strokes similar to those of four-stroke alternative endothermic motors (since the engine can adopt the diesel system or the Otto system for the ignition, hole 1f in figures 3 and 4A indicates the seat of the injection device or, respectively, the spark plug).

Figures 4A-4D illustrate the way in which the races in each of the two hollow spaces are they happen to each other with every 45º of rotation of the rotor and the shaft of drive

Indeed, successive careers in the hollow spaces (3b) and (3b ') adjacent to the surfaces peripherals of the pistons 3b and 3b 'correspond to the positions of the rotor illustrated in the figures.

Position of Figure 4A

(3b):

end of the escape run through of the exhaust duct "1d" and beginning of the suction through the suction duct "1e"; (3b '): ignition and maximum compression stroke.

Position of Figure 4B

(3b):

continuation of the career of aspiration; (3b '): continuation of the expansion run.

Position of Figure 4C

(3b):

maximum suction stroke (3b '): maximum expansion stroke.

Position of Figure 4D

(3b):

compression stroke; (3b '): escape race.

The description above shows that there are two Useful cycles in the engine (one for each hollow space) for each rotor and crank revolution.

Figures 6A-6D show schematically axonometric views of the cylindrical body 1c in figures 2 and 3 and, more precisely, the front view (figures 6A), the plan view from above (figure 6B), the view in plant from below (figure 6C) and side view (figure 6D).

Figures 7A and 7B show respectively the front and side views of the plate 1a shown in the figures
2 and 3

Figures 8A-8E show some axonometric views of a piston of figure 3 and, more precisely, the plan view (figure 8A), the front view (figure 8B), the view exploded from below (figure 8C), the view  in exploded cross section (figure 8D) and side view (figure 8E) of the piston without the apical insert referred to previously.

In the figures, the marked parts have the following meanings:

81: space to accommodate the upper end of the crank and a piston pin 10 (figure 10A, 10B) that acts as a joint,

82: holes in which the ends of the piston pin and roller bearings that retain the piston pin (not shown in the figures),

83: curved groove on the sides of the piston that they act as a seat for a curved metal segment 88 (figure 8B) requested by springs (not shown in the figures) to leaving the seat in order to exert pressure against the wall internal of plates 1a and 1b to ensure a lateral seal,

84: cross-sectional view of a prismatic shaped component that materializes the ends piston apicals,

85: basic end body housing apical 84 designed to fit so that it runs in piston cavities where there are springs (not shown in the figures) requesting said basic body to exit said cavity so as to exert pressure against the cylindrical wall of the stator chamber to ensure an apical seal,

86: side view of the end head apical 84 showing a peripheral rib with a notch designed to allow the entry of one end of the fitted curved segment in groove 83, and

87: spring seat (not shown in the figures) requesting said end of the curved segment fitted in groove 83 to exert pressure against the inner wall of the plates 1a and 1b in order to ensure a lateral seal.

Figures 9A and 9B show (on a reduced scale compared to that used for figures 8), respectively, the top and front views of the cranks 3a, 3a 'and drive shaft 2, while the Figures 10A and 10B respectively show the plan views from the top and side of the piston pin intended to fit with the ends in the holes 82 of each piston (figures 8A-8C).

Figure 9B shows that the ends of crank 3a and 3a 'are shaped like a fork and that the piston pin 10 in its medium part has a section transverse square. Indeed, this part is designed to be clamped in the cavity of said fork as shown in the dashed lines of figure 9B.

Naturally, numerous can be done modifications, adaptations, variations, omissions and substitutions  of elements by other functionally equivalent in forms of embodiment described above without departing from the scope of the invention.

One such variation could concern, for example, to the number of pistons. Indeed, figures 11, 12, 13A and 13B show the equivalent of Figures 3, 4, 9A and 9B if the Engine is made with three rotary pistons. In this case, the sizing criteria and, in particular, the shape of the Stator and piston cavity are similar to the case previous, while the number of useful cycles per revolution of the drive shaft will go from two to three.

From the above description, the advantages of the present invention compared to the technique previous and, in particular, with respect to the Wankel engine. In effect:

-

 there is greater simplicity of construction that derives from the absence of couplings with eccentric cams and wheel couplings gears,

-

 the Useful cycles for each engine revolution are doubled (two piston solution) or triplicate (three solution pistons) with a resulting increase in specific power of the engine, and

-

 be eliminate mobile eccentric masses.

Claims (6)

1. Endothermic motor with rotary pistons (3b, 3b ') whose operating cycle includes some runs of aspiration, compression, expansion and fluid leakage and in which They are planned:

-

 a stator (1) presenting an internal stator chamber shaped Cylindrical closed at its ends by two base plates (1a, 1b) and provided with an exhaust duct (1d) for fluid leakage of the chamber and a suction duct (1e) for the aspiration of fluid into the chamber,

-

 a drive shaft (2) running through said chamber coaxially,

-

 a rotor (3) connected to the drive shaft and which, during its turn, has surfaces facing parts of the surface of the stator chamber and delimiting with said parts variable volume work chambers with the rotation of the tree drive,

at that:

-

 he rotor comprises rods (3a, 3a ') that function as cranks, each of them presenting a connected end rigidly to the drive shaft (2) and the other end articulated with a respective piston (3b, 3b ') so prismatic

-

 saying piston has a convex surface face (3b_, 3b'_) that ends on two opposite sides with rectilinear apical edges (3b ^, 3b '^) parallel to the axis of the drive shaft,

-

 bliss face (3b_, 3b'_), during the rotation of the drive shaft, look always towards parts of the surface of the stator chamber and has a curvature never greater than the curvature of said parts, and

-

 the stator chamber features a cross section with profile oval symmetric with respect to two axes mutually perpendicular (x, y) and is configured so as to ensure with each rotor position a sealed contact with both said Apical edges mentioned, thus defining a hollow space bounded by the surface of the stator chamber and the face of convex surface of the piston and in which the cycle takes place of operation, and

-

 be called "l" and "L" the lengths of the semi-axes more short and longer, respectively, of the ovoidal profile of the chamber of the stator and is called "r" to the value \ sqrt {L2} + l 2, representing the apical edges (3b ^, 3b '^) of each piston a distance of 2 \ cdotr between them,

characterized in that:

-

 he joint axis of each piston is located in the plane defined by the two apical edges and equidistant from the themselves,

-

 the distance from the axis of the joint to the axis of the shaft drive is "r",

-

 he Stator chamber profile is expressed in polar coordinates by the equation \ rho (\ theta) = 2r \ cdot cos ((\ Psi_ {M} - \ Psi_ {m}) without ^ 2 \ theta + \ Psi_ {m})

in which \ Psi_ {M} = arccos (l / 2r) and \ Psi_ {m} = arccos (L / 2r).

2. An endothermic motor according to claim 1, characterized in that the ratio L / l is between 1.5 and 1.35. 3. Endothermic motor according to claim 2, in which the ratio L / l is 1.28. 4. Endothermic motor according to claim 1, in which the stems that function as cranks are located in a diametrically opposite position. 5. Endothermic motor according to claim 1, in which the stems that work as cranks are three and are angularly equidistant from each other. 6. An endothermic motor according to one of the preceding claims, characterized in that the ends of each piston delimited by said apical edges are made in the form of components (84) that can be moved in a direction parallel to the plane defined by the two apical edges and perpendicular to said axes, and are requested by springs towards the surface of the stator chamber to ensure the sealing of the piston at its apical edges.